Do Now:. Circumference What is circumference? Circumference is the distance around a circle.

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Presentation transcript:

Do Now:

Circumference

What is circumference? Circumference is the distance around a circle

To calculate the circumference… We use diameter to calculate circumference, but we need to multiply the diameter by something That is where pi comes in! Circumference = (Diameter)( π )

Pi! For every circle – –If you measure the circumference and the diameter and divide the circumference by the diameter, you will get pi.

Let’s see how close you can get to the actual value of pi!

Finding Circumference Formula: Circumference = (Diameter)( π ) Example: If a circle has a diameter of 3 meters, what is the circumference? Provide an exact answer. Circumference = (Diameter)( π ) Circumference = (3)( π ) Circumference = 3 π Exact Answer

Working Backwards If a circle has a circumference of 12 π meters, what is the radius? Circumference = (Diameter)( π ) 12 π = (Diameter)( π ) 12 = Diameter 6 = Radius

What if there is no pi? The circumference of a circle is meters. Find the radius and round your answer to the nearest whole number. Circumference = (Diameter)( π ) = (Diameter)( 3.14 ) ≈ Diameter 4 ≈ Radius Approximate Answer